Numerous applications exist for selectively dispensing a viscous fluid which is being stored in a reservoir.
There are several known types of dispensing devices which utilize both gravity and mechanical force to dispense viscous fluid through a tube connected to a reservoir. One such type, known generically as "roller"-type dispensers, utilize a flexible tube or hose which is connected to a reservoir. The viscous fluid is gravity fed from the reservoir into the tube, and the tube is then squeezed along at least a portion of its length by a roller or slide to dispense the viscous fluid further through and out of the tube. The mechanical force of the roller on the tube is therefore utilized to dispense the viscous fluid out of the tube. In U.S. Pat. No. 3,881,641, for example, a roller is progressively urged into contact with a flexible tube so that the viscous liquid within the tube is squeezed forward towards the dispensing end of the tube at all times rather than partially forward and partially back upstream towards the reservoir.
Another type of viscous liquid dispensing device is illustrated in U.S. Pat. No. 3,741,439, in which a viscous liquid, e.g., toothpaste, is dispensed through the mechanical force of a moveable lever against a length of tubing connected to a reservoir. The moveable lever is mounted adjacent the tubing and opposite a wall on the other side of the tubing. The fulcrum of the moveable lever is initially at the downstream end of the moveable lever so that the moveable lever forms an inclined surface which moves against the tubing. The degree of inclination is selected so that the upstream lever arm initially presses the tubing against the wall before the downstream lever arm presses against the tubing. When the upstream lever arm has pushed inwardly against the tube as far as possible, the downstream lever arm begins to move inwardly. A nub at the end of the upstream lever arm is also used to restrict flow of viscous liquid in the upstream direction. A separate, positive closure mechanism is constructed adjacent the tubing and located above the orifice at the downstream end to prevent air from entering the tubing through the orifice. Another embodiment of U.S. Pat. No. 3,741,439 has a plunger attached to a lever to close a downstream portion of the tubing, but upward flow through a circuitous route is required.
One type of application in which these dispensing devices are useful is in the dispensing of viscous foodstuffs having fluid characteristics. In addition to the dispensing of beverages, such as milk, fruit drinks and the like, the dispensing of condiments such as ketchup, mustard, relish, cheese sauce and the like may be desired. A consumer may purchase a food product without condiments having been placed thereon, while desiring to place one or more different condiments on these food products.
For example, at sports stadiums and other mass-attendance public events, food products like hot dogs and hamburgers may be sold to consumers who then take the purchased food products to one or more condiment dispensing stations. These dispensing stations will apparently be subject to a high degree of use due to the relatively large number of consumers who will use the dispensing station on any given day or number of days. Since the dispensing stations will be subject to a high level of use, these dispensing stations must be durable enough to withstand the high level of use. Further, the dispensing stations should preferably be of simple design so that operation and maintenance of these dispensing stations can be easily and efficiently achieved.
A need exists for a condiment dispenser that is simple in design and operation and which can employ a direct downward path from a condiment holding reservoir and which has a simple and effective closure mechanism that prevents unwanted discharge.